There have been a number of examples of methods for forming nanomaterials using graphene and metal oxides to take advantage of the unique electrochemical properties of graphene. For example, U.S. patent application Ser. No. 12/462,857 filed Aug. 10, 2009 describes nanocomposite materials having at least two layers. Each layer consists of one metal oxide bonded to at least one graphene layer. The nanocomposite materials will typically have many alternating layers of metal oxides and graphene layers, bonded in a sandwich type construction and will be incorporated into a electrochemical or energy storage device.
U.S. patent application Ser. No. 12/553,527 filed Sep. 3, 2009 describes a nanocomposite material formed of graphene and a mesoporous metal oxide having a demonstrated specific capacity of more than 200 F/g with particular utility when employed in supercapacitor applications. These nanocomposite materials by forming a mixture of graphene, a surfactant, and a metal oxide precursor and then precipitating the metal oxide precursor with the surfactant from the mixture to form a mesoporous metal oxide. The mesoporous metal oxide is then deposited onto a surface of the graphene.
These and other prior art devices typically form the nanocomposite materials using a metal oxides in a salt form, such as lithium titanate (Li4Ti5O12,) as a precursor material. While this Li4Ti5O12 material has been shown to work well in these applications, it is expensive and thus may not be suited for certain high volume applications.
Many of these metal oxides are widely known as inexpensive materials, but are also widely known as poor electrical conductors. For example, titania of the form TiOx in its common forms of its anatase or rutile is widely known as an inexpensive material, but is also widely known as a poor electrical conductor. Therefore, those of ordinary skill in the art have not used these metal oxides, such as titania, as an anode material, or in applications where it would be a precursor to an anode material.
Accordingly, there exists a need for low cost metal oxides that can be successfully utilized as an anode material, or as a precursor to an anode material in applications where it would be combined with graphene. The present invention fulfills that need.